This invention relates, in general, to speed control circuits, and more particularly, to an integrated circuit speed controller particularly useful for controlling the speed of a direct current component.
It is well known that SCRs are well suited as speed controllers for alternating current motors. Well known speed controllers for direct current motors are not as refined as speed controllers for alternating current motors. As an example, potentiometers or dropping resistors have been used to control the speed of direct current motors. This is highly inefficient since the potentiometer or resistor dissipates a considerable amount of power. Of course, a speed controller for a direct current motor could be built from discrete semiconductor devices; however, such a speed controller would be rather large and expensive due to the amount of labor required to assemble such a controller. In addition, such a controller would not necessarily have the capability of over current and over temperature protection. Therefore, it would be desirable to have a direct current motor speed controller built on a single integrated circuit chip.
Accordingly, it is an object of the present invention to provide an improved monolithic integrated circuit speed controller.
Another object of the present invention is to provide an integrated circuit speed controller useful for controlling the speed of a direct current component and which has self-contained over current and over temperature protection.
Yet another object of the present invention is to provide an integrated circuit speed controller which can be manufactured using CMOS processes.